tank rebuild this wknd, sudden hair/thread algae outbreak, what do I do?

I'm about to rebuild my 20L and try some worm casing/mineralized top soil substrate. Originally, i planned to move my betta and plants to a smaller tank until the 20 gallon is ready.

After noticing whispy algae trailing from my Vals and other plants, I'm afraid to re-introduce them back into my new setup this weekend. Can I quarantine the plants into a smaller container overdosed with Excel to maybe kill the algae before adding them to the tank?

Would a carefully measured bleach dip clean them up since they'll be uprooted and awaiting their new home soon?

BTW, I quit dosing and shut off the c02 a week ago in hopes of saving it for the new setup. I'm guessing that was the cause of this outbreak.